The present invention relates to an interphase insulating sheet, and more particularly to an interphase insulating sheet for insulating the phase windings of a stator from one another.
The stator of a multiphase motor, for example, a three-phase motor, includes a stator core with plural slots and stator windings. The stator windings corresponding to a U-phase winding, a V-phase winding and a W-phase winding are sequentially and circumferentially arranged at positions of the stator core which corresponds to the exciting position of each phase. Namely, the stator includes a three-phase distributed winding. Each of the phase windings is composed of plural conductors coated with enamel. The part of each phase winding which extends between the slots is located at the end of the stator core thereby to form a coil end.
In order to secure insulation of the phase windings from one another at the coil end of the above-described stator, a sheet-like insulating member, which is referred to as an interphase insulating sheet, is inserted between any two of the phase windings. That is, two interphase insulating sheets are inserted between the U-phase winding, the V-phase winding and the W-phase winding thereby to keep each phase winding out of contact with the other phase windings.
Unexamined Japanese Patent Publication No. 2003-333785 discloses an example of a stator using the above interphase insulating sheet. In the case that such an interphase insulating sheet is used for insertion into the stator, however, the insulating sheet may be moved toward the coil end of the stator or away from the stator core due to work operation of provisional lacing or shaping of coil ends which is usually performed subsequently to the insertion process of insulating sheet, with the result that part of the phase winding may come into contact with other phase winding. Therefore, it has been necessary that the interphase insulating sheet moved away from the stator core should be pushed back toward the stator core by hand or something for ensuring insulation of the phase windings.
The present invention is directed to an interphase insulating sheet that is hard to move away from a stator core after the interphase insulating sheet has been inserted in a stator.